4.10  Vérificateur mémoire 1/3

• Outil valgrind.
• Exemple de vérification d’initialisation de variable :

  rex@monet:/tmp/Debug$ valgrind ./segfault 
  ==8756== Memcheck, a memory error detector
  ==8756== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
  ==8756== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
  ==8756== Command: ./segfault
  ==8756== 
  ==8756== Use of uninitialised value of size 4
  ==8756==    at 0x804840A: main (segfault.c:6)
  ...
  

• Exemple de vérification de débordement de blocs alloués :

  $ cat -b debordement.c
       1 #include <stdio.h>
       2 #include <stdlib.h>
       3 #define MAX_ALLOC 10
       4 int main(void){
       5 char *tab=malloc(MAX_ALLOC*sizeof(char));
       6 int i;
       7 for(i=1;i<=MAX_ALLOC;i++) tab[i]=i;
       8 for(i=1;i<=MAX_ALLOC;i++) printf("%d\n",tab[i]);
       9 return 0;
      10 }
  $ valgrind ./debordement
  ==5345== Memcheck, a memory error detector
  ...
  ==5345== Invalid write of size 1
  ==5345==    at 0x804847D: main (debordement.c:7)
  ==5345==  Address 0x41a8032 is 0 bytes after a block of size 10 alloc'd
  ==5345==    at 0x4028308: malloc (vg_replace_malloc.c:263)
  ==5345==    by 0x8048460: main (debordement.c:5)
  ...